Control information configuration in wireless communications

ABSTRACT

A wireless communication method is provided to include: sending, by a user device, a first message to a network device in a wireless network to initiate a 2-step random access to the wireless network; and receiving, in response to the first message, a second message to perform the 2-step random access, the second message including a field indicating whether a transport block size of a payload of the second message is scaled.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2019/110717, filed on Oct. 12, 2019, the contents of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

This patent document generally relates to systems, devices, andtechniques for wireless communications.

BACKGROUND

Wireless communication technologies are moving the world toward anincreasingly connected and networked society. The rapid growth ofwireless communications and advances in technology has led to greaterdemand for capacity and connectivity. Other aspects, such as energyconsumption, device cost, spectral efficiency, and latency are alsoimportant to meeting the needs of various communication scenarios. Incomparison with the existing wireless networks, next generation systemsand wireless communication techniques need to provide support for anincreased number of users and devices.

SUMMARY

This document relates to methods, systems, and devices for controlinformation configuration in wireless communications.

In one aspect, a wireless communication method is disclosed. Thewireless communication method is provided to include sending, by a userdevice, a first message to a network device in a wireless network toinitiate a 2-step random access to the wireless network; and receiving,in response to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled.

In another aspect, a wireless communication method is disclosed. Thewireless communication method is provided to include receiving, by anetwork device, a first message from a user device in a wireless networkto initiate a 2-step random access to the wireless network; and sending,in response to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled.

In another aspect, a wireless communication apparatus comprising aprocessor configured to perform the disclosed methods is disclosed.

In another aspect, a computer readable medium having code stored thereonis disclosed. The code, when implemented by a processor, causes theprocessor to implement a method described in the present document.

These, and other features, are described in the present document.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows an example of wireless communication including a basestation (BS) and user equipment (UE) based on some implementations ofthe disclosed technology.

FIG. 2 shows an example of a block diagram of a portion of an apparatusbased on some implementations of the disclosed technology.

FIG. 3 shows a contention-based four-step random access procedurebetween a user equipment and a network side communication node.

FIG. 4 shows an example of a two-step random access procedure between auser equipment and a network side communication node.

FIG. 5 shows examples of contents included in the msgB PDSCH.

FIG. 6 shows an example of MAC (Medium Access Control) structure of msgBPDSCH.

FIG. 7 shows an example of a table illustrating DCI (Downlink ControlInformation) formats.

FIG. 8 shows an example of SuccessRAR structure included in the msgBPDSCH.

FIG. 9 shows an example of a table illustrating DCI formats.

FIGS. 10 and 11 show example flowcharts of wireless communicationmethods based on some implementations of the disclosed technology.

DETAILED DESCRIPTION

The disclosed technology provides implementations and examples ofcontrol information configuration in wireless communications. In someimplementations, the suggested control information configuration enablesthe two-step random access procedures between a user device and anetwork device. While 5G terminology is used in some cases to facilitateunderstanding of the disclosed techniques, which may be applied towireless systems and devices that use communication protocols other than5G or 3GPP protocols.

In the 5th Generation (5G) New Radio (NR) mobile networks, a userequipment (UE) is required to obtain uplink timing synchronization anddownlink timing synchronization with a base station (BS) before a userequipment (UE) can send data to a base station (BS). The uplink timingsynchronization can be achieved by performing a random access procedure(RACH). The random access procedure is to be provided to meet the demandfor faster and efficient communications. This document proposes variousconfiguration schemes for downlink control information in wirelesscommunications.

FIG. 1 shows an example of a wireless communication system (e.g., a 5Gor NR cellular network) that includes a BS 120 and one or more userequipment (UE) 111, 112 and 113. In some embodiments, the UEs access theBS (e.g., the network) using implementations of the disclosed technology(131, 132, 133), which then enables subsequent communication (141, 142,143) from the BS to the UEs. The UE may be, for example, a smartphone, atablet, a mobile computer, a machine to machine (M2M) device, anInternet of Things (IoT) device, and so on. Although FIG. 1 shows the BS120, other network side communication nodes can be implemented tocommunicate with the UE. For example, the network side communicationnode or the BS 102 can include a node B, an E-UTRA Node B (also known asEvolved Node B, eNodeB or eNB), a gNodeB (also known as gNB) in newradio (NR) technology, a pico station, a femto station, or others.

FIG. 2 shows an example of a block diagram representation of a portionof an apparatus. An apparatus 210 such as a base station or a wirelessdevice (or UE) can include processor electronics 220 such as amicroprocessor that implements one or more of the techniques presentedin this document. The apparatus 210 can include transceiver electronics230 to send and/or receive wireless signals over one or morecommunication interfaces such as antenna 240. The apparatus 210 caninclude other communication interfaces for transmitting and receivingdata. The apparatus 210 can include one or more memories (not explicitlyshown) configured to store information such as data and/or instructions.In some implementations, the processor electronics 220 can include atleast a portion of transceiver electronics 230. In some embodiments, atleast some of the disclosed techniques, modules or functions areimplemented using the apparatus 210.

The traditional contention-based RACH procedure for NR is the four-stepRACH. FIG. 3 shows a contention-based four-step random access procedurebetween the UE and the network side communication node (e.g., eNode B).At the first step, the UE sends a RACH preamble (msg1) to a networkdevice. At the second step, in response to the RACH preamble, thenetwork device sends a random access response (msg2). At the third step,the UE sends Layer 2/Layer 3 (L2/L3) message (msg3) to the network. Atthe fourth step, the network sends the contention resolution message(msg4) to the UE. Since the traditional contention-based RACH procedurerequires four steps, the latency can become a problem. Thus, a two-stepRACH, which can significantly reduce the overall initial access latency,is getting more attention recently.

FIG. 4 shows an example of a two-step RACH process between a UE and anetwork side communication node (e.g., gNB). At the first step of thetwo-step RACH process, a first message (msgA) is transmitted from the UEto gNB. At the second step of the two-step RACH process, a secondmessage (msgB) is transmitted from gNB to the UE. The msgA of thetwo-step RACH merges the contents of the msg1 and the msg3 of thecontention-based four-step RACH, and the msgB of two-step RACH mergesthe contents of msg2 and msg4 of the contention-based four-step RACH.The channel structure of msgA corresponds to a preamble with a PUSCH(Physical Uplink Shared Channel) carrying payload which includes atleast the content of msg3 in the traditional 4-step RACH. In someimplementations, the payload may include a contention resolution ID andothers in IDLE or inactive mode. In some implementations, the payloadmay include at least the UE's C-RNTI (Cell-Radio Network TemporaryIdentifier) in connected mode. The content of the msgB may include thecontents of msg2 and msg4 of the contention-based four-step RACH and themsgB is configured to handle the contention resolution function for2-step RACH.

In some implementations, during the two-step RACH, the gNB transmits themsgB which includes the physical downlink control channel (PDCCH) andphysical downlink shared channel (PDSCH). The msgB PDSCH may bescheduled by the DCI (Downlink Control Information) of msgB PDCCH. ThemsgB PDCCH and msgB PDSCH are PDCCH and PDSCH that are associated withthe msgB. The msgB PDCCH is addressed or associated with a msgB radionetwork temporary identifier (msgB-RNTI) or the UE's C-RNTI which hastransmitted the msgA at the first step of the two-step RACH. In someimplementations, the msgB PDCCH is scrambled by the msgB-RNTI or C-RNTI.The msgB-RNTI may be a random access RNTI (RA-RNTI) or a new RNTI whichis separated from the traditional message 2 RA-RNTI. MsgB will be sentfrom the gNB to the UE if the preamble in msgA has been detected by thegNB. Depending on whether the payload in msgA has been successfullydecoded, the content of msgB which embedded in the msgB PDSCH may bedifferent.

The msgB PDSCH may include three kinds of function elements:‘SuccessRAR’, ‘FallbackRAR’, or ‘Backoff indicator (BI).’ The SuccessRARis a random access response after the msgA PUSCH has been successfullyreceived and decoded by the base station. The FallbackRAR is a randomaccess response after the preamble sequence in the msgA is successfullyreceived by the base station but the PUSCH has been unsuccessfullydecoded by the base station. The Backoff indicator is a general back-offindication which has the same function as the LTE backoff indicator.FIG. 5 shows examples of contents included in the msgB PDSCH includingsuccess RAR, fallback RAR, and backoff indicator. For the case both themsgA preamble and payload are successfully detected and decoded, theSuccessRAR in the msgB may include contention resolution ID which istransmitted in msgA, C-RNTI assigned for the UE or TA command. For thecase that the preamble is successfully detected but the payload in PUSCHis not successfully decoded, the RACH procedure will fall back totraditional four-step RACH. The FallbackRAR could be identical to legacymsg2 which includes three fields: TC-RNTI, UL grant and TA command. OrRAPID will be added into FallbackRAR in addition with the previous threefields. In traditional 4-step RACH, the RAPID (Random Access PreambleIdentifier) is included in the msg2 MAC subheader.

The msgB PDSCH may contains the SuccessRAR, FallbackRAR, or Backoffindicator together or any combination of the three function elements.FIG. 6 shows an example of a MAC (Medium Access Control) PDU (ProtocolData Unit) structure of msgB PDSCH. In FIG. 6, the MAC PDU includesmultiple MAC subPDUs (e.g., MACsubPDU1 to MACsubPDU n+1) which carrydifferent types of MAC subheader and/or different types of MAC RAR(SuccessRAR or FallbackRAR). FIG. 6 shows the example only and thus theorder and the contents of the msgB PDSCH are not limited to thisexample. In some implementations, there can be multiple SuccessRARsmultiplexed in one msgB for multiple UEs. And it is also possible toinclude the FallbackRARs for one or a group of UEs identified by thesame msgB RA-RNTI. The Backoff indicator can be carried in the MACsubheader.

The HARQ (Hybrid Automatic Repeat Request)-ACK feedback for the UEreception of SuccessRAR in msgB is needed to indicate that thesuccessRAR has been successfully received by the corresponding UE whichidentified by the Contention resolution ID. When the HARQ-ACK isreceived by gNB, gNB will not retransmit the msgB for the UEs whichfeedback the ACK.

The UE my need to feedback the ACK by using the PUCCH resources. ThePUCCH related resources may be indicated by the msgB PDCCH or msgB PDSCHin addition to some configurations in system information. The DCI format1-0 for scheduling the PDSCH can be reused for msgB PDCCH. The DCI inDCI format 1-0 for msg2 of the tradition 4-step RACH is CRC (CyclicRedundancy Check) scrambled by RA-RNTI, and the DCI in DCI format 1-0for msg4 of the tradition 4-step RACH is CRC scrambled by TC-RNTI orC-RNTI. The supported DCI which is carried by the DCI format 1-0scrambled by different RNTI are shown in the table in FIG. 7.

FIG. 7 shows four different DCI formats that are respectively scrambledby RA-RNTI, TC-RNTI, msgB-RNTI, and C-RNTI. Among the four DCI formatsshown I FIG. 7, the DCI format scrambled by msgB-RNTI is used toimplement the 2-step random access as suggested in some implementationsof the disclosed technology. In FIG. 7, the DCI format scrambled bymsgB-RNTI is illustrated with the concept of the reinterpretation ascompared to the interpretations of corresponding fields in the DCIformats scrambled by RA-RNTI, TC-RNTI, and C-RNTI. From FIG. 7, it isobserved that the DCI format 1_0 with CRC scrambled by TC-RNTI or C-RNTIhas the fields of PUCCH resource indication such as: PUCCH resourceindicator, TPC command for scheduled PUCCH, PDSCH-to-HARQ_feedbacktiming indicator, and the fields of HARQ indication for downlink msgBsuch as: new data indicator, redundancy version, HARQ process number.The two fields are needed for PUCCH transmission and msgBretransmission. Thus, the msgB PDCCH DCI is better to reuse all thefields in DCI format 1-0 CRC scrambled by TC-RNTI or C-RNTI but CRCscrambling sequence is replaced by msgB-RNTI. Furthermore, some revisionor supplement based on the fields in DCI format 1-0 CRC scrambled byTC-RNTI or C-RNTI may be needed for msgB PDCCH DCI format.

The DCI format 1-0 CRC scrambled by C-RNTI for the 2-step RACH msgBPDCCH is valid in the case that the msgA transmitted with C-RNTI inPUSCH. If msgA is transmitted with contention resolution ID in PUSCH,the msgB PDCCH DCI could be modified based on the DCI format 1-0 CRCscrambled by TC-RNTI.

As previously mentioned, in some implementations, there may be multipleSuccessRARs multiplexed in one msgB for multiple UEs. And the HARQ-ACKfeedback carried in PUCCHs for reception of SuccessRARs are needed. Thefield of “TPC command for scheduled PUCCH” in DCI format 1-0 CRCscrambled by TC-RNTI may be used for only one UE TPC command indication,not for multiple UEs. The total number of bits in DCI is limited and notallowed to change as the backward compatible reason, so a better way toindicate multiple UE's PUCCH TPC command is to include the 2 bit TPCcommand per UE in the content of successRAR of each specific UE. Forexample, in FIG. 8, 2 bits in successRAR structure are provided for “TPCcommand for scheduled PUCCH.” The 2 bits of “TPC command for scheduledPUCCH” in DCI format 1-0 CRC scrambled by msgB-RNTI can be reserved orleft empty.

From FIG. 7, it is also observed that the TB scaling field in DCI format1-0 CRC scrambled by RA-RNTI is absent in the DCI format 1-0 CRCscrambled by msgB-RNTI (or TC-RNTI). The TB scaling is an importantparameter for downlink initial access message. TB scaling is configuredto scale the transport block (TB) size of downlink payload of initialaccess message for the purpose of reducing the code rate and improvingthe robustness of downlink signaling reception. It would be verybeneficial that this TB scaling information is included as the DCIinformation for msgB. In some implementations, the TB scalinginformation includes i) whether the TB size of the payload of the msgBis scaled. In some implementation, the TB scaling information furtherincludes how to scale the msgB, e.g., the scaling factor. The typical TBscaling factor can be set such that 00 indicates 100%, 01 indicates 50%,and 10 indicates 25%.

To include the TB scaling information, some reserved bits or empty bitsin DCI format 1-0 CRC scrambled by msgB-RNTI for msgB can bereinterpreted as the TB scaling field. As the example, the table asshown in FIG. 7 shows that the reserved 2 bits for “Downlink assignmentindex” or the reserved bits “TP Command for scheduled PUCCH” can bereinterpreted as the TB scaling field. When the structure (e.g., thefields with the specific function in DCI format and the value range ofeach fields) of DCI format 1-0 CRC scrambled by msgB-RNTI is modifiedfrom that of the legacy format, corresponding fields, for example,“Downlink assignment index” or the reserved bits “TP Command forscheduled PUCCH,” in DCI format 1-0 CRC scrambled by msgB-RNTI isreserved. In this case, the reserved bits in the corresponding fieldscan be reinterpreted as the TB scaling field. In some implementation,when the structure of DCI format 1-0 CRC scrambled by msgB-RNTI is sameas that of the legacy format, corresponding fields, for example,“Downlink assignment index” or the reserved bits “TP Command forscheduled PUCCH,” in DCI format 1-0 CRC scrambled by msgB-RNTI is notreserved. In this case, the reserved bits in the corresponding fieldscan be reinterpreted as the TB scaling field. “Downlink assignmentindex” is original as the counter of DAI (Downlink Assignment Index) butnot really used in DCI format 1-0 CRC scrambled by msgB-RNTI.

If the “TPC command for scheduled PUCCH” per UE is indicated in eachUE's successRAR, the 2 bits of TPC command for scheduled PUCCH in DCIcan be reserved and reinterpreted as the TB scaling field.

In case that the successRAR in msgB is transmitted with SRB (SignalingRadio Bear) data, it is not allowed to multiplex multiple UEssuccessRARs in msgB. In this case, the “TPC command for scheduled PUCCH”in DCI information can be maintained in DCI and doesn't need to bereserved.

In case that the successRAR in msgB is transmitted without SRB data, itis allowed to multiplex multiple UEs successRARs in msgB. In this case,the “TPC command for scheduled PUCCH” in DCI can be either reserved orkept in DCI information. If this field in DCI is kept, it is notmandatory that the “TPC command for scheduled PUCCH” is provided in allsuccessRARs in one msgB. At least one UE's “TPC command for scheduledPUCCH” is provided in DCI and other's “TPC command for scheduled PUCCH”is provided in successRARs.

FIG. 9 shows an example of a table illustrating a DCI format. Comparedto the table in FIG. 7 in which the reinterpretation of some fields isillustrated for the DCI format with CRC scrambled by msgB-RNTI, the DCIformat shown in FIG. 9 shows the final fields included in the DCI formatwith CRC scrambled by msgB-RNTI. In FIG. 9, the structure of the DCIformat 1_0 with CRC scrambled by msgB-RNTI includes the identifier forDCI format, frequency domain resource assignment, time domain resourceassignment, VRB-to-PRB mapping, Modulation and coding scheme and TBscaling. And other fields just like new data indicator, Redundancyversion, HARQ process number, TPC command for scheduled PUCCH, PUCCHresource indicator, PDSCH-to-HARQ_feedback timing indicator could beoptionally included in the structure or be reserved in the structure.The structure of the DCI format means fields with the specific functionin DCI format and the number of bits in each field. The sequence ororder of each field is not included in the definition of structure andthus can be changed in various manners. Downlink assignment index is notused for DCI format 1_0 with CRC scrambled by msgB-RNTI. In someimplementations, the same payload size with other legacy DCI format 1_0can be maintained in the DCI format.

FIG. 10 shows an example of a wireless communication scheme based onsome implementations of the disclosed technology. At step 1010, themethod includes sending, by a user device, a first message to a networkdevice in a wireless network to initiate a 2-step random access to thewireless network. At step 1020, the method includes receiving, inresponse to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled.

FIG. 11 shows another example of a wireless communication scheme basedon some implementations of the disclosed technology. At step 1110, themethod includes receiving, by a network device, a first message from auser device in a wireless network to initiate a 2-step random access tothe wireless network. At step 1120, the method includes sending, inresponse to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled.

Additional features of the above-described methods/techniques that maybe preferably implemented in some implementations are described belowusing a clause-based description format.

1. A wireless communication method, including: sending, by a userdevice, a first message to a network device in a wireless network toinitiate a 2-step random access to the wireless network; and receiving,in response to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled. Thenetwork device may include the BS 120 as shown in FIG. 1 and the userdevice may include the UE as shown in FIG. 1. In some implementations,the 2-step random access to the wireless network is shown in FIG. 4.Examples of the field indicating whether the transport block size of thepayload of the second message is scaled are discussed with reference toFIGS. 7-9.

2. The wireless communication method of clause 1, wherein the field isat a position in the second message at which a legacy format comprises areserve bit or an empty bit.

3. The wireless communication method of clause 1, wherein the fieldfurther indicates a scaling factor for the second message.

4. The wireless communication method of clause 1, wherein the secondmessage is scrambled by a first identifier specific to the secondmessage.

5. The wireless communication method of clause 2, wherein the secondmessage includes downlink control information having a differentstructure from that of the legacy format.

6. The wireless communication method of clause 2, wherein the secondmessage includes downlink control information having a same structure asthat of the legacy format.

7. The wireless communication method of clause 4, wherein the firstidentifier is msgB-RNTI (Radio Network Temporary Identifier).

8. The wireless communication method of clause 5 or 6, wherein thelegacy format is scrambled by a RA (Random Access)-RNTI, TC (TemporaryCell)-RNTI, or C (Cell)-RNTI.

9. The wireless communication method of clause 1, wherein the secondmessage includes a PDCCH (Physical Downlink Control Channel) and PDSCH(Physical Downlink Shared Channel).

10. The wireless communication method of clause 9, wherein the PDSCHincludes at least one of a first element corresponding to a response toa reception of a PUSCH (Physical Uplink Shared Channel) included in thefirst message and a successful decoding of the PUSCH, a second elementcorresponding to a response to a reception of a preamble sequence in thefirst message but an unsuccessful decoding of the PUSCH, or a thirdelement corresponding to a back-off indication.

11. The wireless communication method of clause 10, wherein the firstelement includes at least one of a contention resolution ID, C-RNTIassigned for the user device, or a TA (Timing Advance) command.

12. The wireless communication method of clause 10, wherein the secondelement includes at least one of a preamble identifier, TC_RNTI, UL(uplink) Grant, or a TA command.

13. The wireless communication method of clause 10, wherein the PDSCHincludes a mac structure including multiple MAC sub PDUs.

14. A wireless communication method, including: receiving, by a networkdevice, a first message from a user device in a wireless network toinitiate a 2-step random access to the wireless network; and sending, inresponse to the first message, a second message to perform the 2-steprandom access, the second message including a field indicating whether atransport block size of a payload of the second message is scaled. Thenetwork device may include the BS 120 as shown in FIG. 1 and the userdevice may include the UE as shown in FIG. 1. In some implementations,the 2-step random access to the wireless network is shown in FIG. 4.Examples of the field indicating whether the transport block size of thepayload of the second message is scaled are discussed with reference toFIGS. 7-9.

15. The wireless communication method of clause 14, wherein the field isat a position in the second message at which a legacy format comprises areserve bit or an empty bit.

16. The wireless communication method of clause 14, wherein the fieldfurther indicates a scaling factor for the second message.

17. The wireless communication method of clause 14, wherein the secondmessage is scrambled by a first identifier specific to the secondmessage.

18. The wireless communication method of clause 15, wherein the secondmessage includes downlink control information having a differentstructure from that of the legacy format.

19. The wireless communication method of clause 15, wherein the secondmessage includes downlink control information having a same structure asthat of the legacy format.

20. The wireless communication method of clause 17, wherein the firstidentifier is msgB-RNTI (Radio Network Temporary Identifier).

21. The wireless communication method of clause 18 or 19, wherein thelegacy format is scrambled by a RA (Random Access)-RNTI, TC (TemporaryCell)-RNTI, or C (Cell)-RNTI.

22. The wireless communication method of clause 14, wherein the secondmessage includes a PDCCH (Physical Downlink Control Channel) and PDSCH(Physical Downlink Shared Channel).

23. The wireless communication method of clause 22, wherein the PDSCHincludes at least one of a first element corresponding to a response toa reception of a PUSCH (Physical Uplink Shared Channel) included in thefirst message and a successful decoding of the PUSCH, a second elementcorresponding to a response to a reception of a preamble sequence in thefirst message but an unsuccessful decoding of the PUSCH, or a thirdelement corresponding to a back-off indication.

24. The wireless communication method of clause 23, wherein the firstelement includes at least one of a contention resolution ID, C-RNTIassigned for the user device, or a TA (Timing Advance) command.

25. The wireless communication method of clause 23, wherein the secondelement includes at least one of a preamble identifier, TC_RNTI, UL(uplink) Grant, or a TA command.

26. The wireless communication method of clause 23, wherein the PDSCHincludes a mac structure including multiple MAC sub PDUs.

27. A communication apparatus comprising a processor configured toimplement a method recited in any one or more of clauses 1 to 26.

28. A computer readable medium having code stored thereon, the code,when executed, causing a processor to implement a method recited in anyone or more of clauses 1 to 26.

It is intended that the specification, together with the drawings, beconsidered exemplary only, where exemplary means an example and, unlessotherwise stated, does not imply an ideal or a preferred embodiment. Asused herein, the use of “or” is intended to include “and/or”, unless thecontext clearly indicates otherwise.

Some of the embodiments described herein are described in the generalcontext of methods or processes, which may be implemented in oneembodiment by a computer program product, embodied in acomputer-readable medium, including computer-executable instructions,such as program code, executed by computers in networked environments. Acomputer-readable medium may include removable and non-removable storagedevices including, but not limited to, Read Only Memory (ROM), RandomAccess Memory (RAM), compact discs (CDs), digital versatile discs (DVD),etc. Therefore, the computer-readable media can include a non-transitorystorage media. Generally, program modules may include routines,programs, objects, components, data structures, etc. that performparticular tasks or implement particular abstract data types. Computer-or processor-executable instructions, associated data structures, andprogram modules represent examples of program code for executing stepsof the methods disclosed herein. The particular sequence of suchexecutable instructions or associated data structures representsexamples of corresponding acts for implementing the functions describedin such steps or processes.

Some of the disclosed embodiments can be implemented as devices ormodules using hardware circuits, software, or combinations thereof. Forexample, a hardware circuit implementation can include discrete analogand/or digital components that are, for example, integrated as part of aprinted circuit board. Alternatively, or additionally, the disclosedcomponents or modules can be implemented as an Application SpecificIntegrated Circuit (ASIC) and/or as a Field Programmable Gate Array(FPGA) device. Some implementations may additionally or alternativelyinclude a digital signal processor (DSP) that is a specializedmicroprocessor with an architecture optimized for the operational needsof digital signal processing associated with the disclosedfunctionalities of this application. Similarly, the various componentsor sub-components within each module may be implemented in software,hardware or firmware. The connectivity between the modules and/orcomponents within the modules may be provided using any one of theconnectivity methods and media that is known in the art, including, butnot limited to, communications over the Internet, wired, or wirelessnetworks using the appropriate protocols.

While this document contains many specifics, these should not beconstrued as limitations on the scope of an invention that is claimed orof what may be claimed, but rather as descriptions of features specificto particular embodiments. Certain features that are described in thisdocument in the context of separate embodiments can also be implementedin combination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesub-combination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asub-combination or a variation of a sub-combination. Similarly, whileoperations are depicted in the drawings in a particular order, thisshould not be understood as requiring that such operations be performedin the particular order shown or in sequential order, or that allillustrated operations be performed, to achieve desirable results.

Only a few implementations and examples are described and otherimplementations, enhancements and variations can be made based on whatis described and illustrated in this disclosure.

What is claimed is:
 1. A wireless communication method, including:sending, by a user device, a first message to a network device in awireless network to initiate a 2-step random access to the wirelessnetwork; and receiving, in response to the first message, a secondmessage to perform the 2-step random access, the second messageincluding a field indicating whether a transport block size of a payloadof the second message is scaled.
 2. The wireless communication method ofclaim 1, wherein the field is at a position in the second message atwhich a legacy format comprises a reserve bit or an empty bit.
 3. Thewireless communication method of claim 1, wherein the field furtherindicates a scaling factor for the second message.
 4. The wirelesscommunication method of claim 1, wherein the second message is scrambledby a first identifier specific to the second message.
 5. The wirelesscommunication method of claim 2, wherein the second message includesdownlink control information having a different structure from that ofthe legacy format or a same structure as that of the legacy format, thelegacy format being scrambled by a RA (Random Access)-RNTI, TC(Temporary Cell)-RNTI, or C (Cell)-RNTI.
 6. The wireless communicationmethod of claim 1, wherein the second message includes a PDCCH (PhysicalDownlink Control Channel) and PDSCH (Physical Downlink Shared Channel).7. The wireless communication method of claim 6, wherein the PDSCHincludes at least one of a first element corresponding to a response toa reception of a PUSCH (Physical Uplink Shared Channel) included in thefirst message and a successful decoding of the PUSCH, a second elementcorresponding to a response to a reception of a preamble sequence in thefirst message but an unsuccessful decoding of the PUSCH, or a thirdelement corresponding to a back-off indication.
 8. The wirelesscommunication method of claim 7, wherein the first element includes atleast one of a contention resolution ID, C-RNTI assigned for the userdevice, or a TA (Timing Advance) command, wherein the second elementincludes at least one of a preamble identifier, TC_RNTI, UL (uplink)Grant, or a TA command, and wherein the PDSCH includes a mac structureincluding multiple MAC sub PDUs.
 9. A wireless communication method,including: receiving, by a network device, a first message from a userdevice in a wireless network to initiate a 2-step random access to thewireless network; and sending, in response to the first message, asecond message to perform the 2-step random access, the second messageincluding a field indicating whether a transport block size of a payloadof the second message is scaled.
 10. The wireless communication methodof claim 9, wherein the field is at a position in the second message atwhich a legacy format comprises a reserve bit or an empty bit.
 11. Thewireless communication method of claim 9, wherein the field furtherindicates a scaling factor for the second message.
 12. The wirelesscommunication method of claim 9, wherein the second message is scrambledby a first identifier specific to the second message.
 13. The wirelesscommunication method of claim 10, wherein the second message includesdownlink control information having a different structure from that ofthe legacy format or a same structure as that of the legacy format, thelegacy format scrambled by a RA (Random Access)-RNTI, TC (TemporaryCell)-RNTI, or C (Cell)-RNTI.
 14. The wireless communication method ofclaim 9, wherein the second message includes a PDCCH (Physical DownlinkControl Channel) and PDSCH (Physical Downlink Shared Channel).
 15. Thewireless communication method of claim 14, wherein the PDSCH includes atleast one of a first element corresponding to a response to a receptionof a PUSCH (Physical Uplink Shared Channel) included in the firstmessage and a successful decoding of the PUSCH, a second elementcorresponding to a response to a reception of a preamble sequence in thefirst message but an unsuccessful decoding of the PUSCH, or a thirdelement corresponding to a back-off indication.
 16. The wirelesscommunication method of claim 15, wherein the first element includes atleast one of a contention resolution ID, C-RNTI assigned for the userdevice, or a TA (Timing Advance) command, wherein the second elementincludes at least one of a preamble identifier, TC_RNTI, UL (uplink)Grant, or a TA command, and wherein the PDSCH includes a mac structureincluding multiple MAC sub PDUs.
 17. A communication apparatuscomprising a processor configured to implement a method comprising:sending, by a user device, a first message to a network device in awireless network to initiate a 2-step random access to the wirelessnetwork; and receiving, in response to the first message, a secondmessage to perform the 2-step random access, the second messageincluding a field indicating whether a transport block size of a payloadof the second message is scaled.
 18. The communication apparatus ofclaim 17, wherein the field is at a position in the second message atwhich a legacy format comprises a reserve bit or an empty bit.
 19. Thewireless communication method of claim 17, wherein the field furtherindicates a scaling factor for the second message.
 20. The wirelesscommunication method of claim 17, wherein the second message isscrambled by a first identifier specific to the second message.